Comparing different methods for homocysteine determination.

Slightly elevated values of homocysteine are commonly associated with thromboembolic diseases, while high values can be found in patients with congenital metabolic defects or nutritional problems. The clinical use of homocysteine as an independent marker of cardiovascular disease was limited in the past by technical problems with its measurement, the instrumentation (HPLC, radioenzymatic assays, gas chromatography-mass spectrometry, etc.) and the necessary skills required. Commercially available immunoassays now permit a simpler and more rapid measurement of homocysteine, that is more suitable for routine clinical laboratories; in this paper we analyze the results obtained by using three fully automated methods for homocysteine determination (Abbott IMx immunoassay, Abbott AxSYM immunoassay and Immulite 2000 homocysteine immunoassay) and their correlation with the widely used HPLC method. The results clearly indicate that all three automated immunochemical methods correlate well with the HPLC method (slope 0.97-1.03; intercept 0.95-1.91 with a recovery above 95% for all three methods).     

Cerebellar connections with the motor cortex and the arcuate premotor area: an analysis employing retrograde transneuronal transport of WGA-HRP

We have employed transneuronal transport to examine the anatomical relationships between the deep cerebellar nuclei and 2 cortical motor areas: the primary motor cortex and the arcuate premotor area (APA). In the same animals, we have also examined the patterns of labeling in the thalamus and the red nucleus to provide evidence for the potential routes of transneuronal transport to the cerebellum. When the appropriate technical procedures were employed, cortical injections of wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) resulted in transneuronal labeling within portions of the contralateral deep cerebellar nuclei. Injections into the primary motor cortex labeled neurons in the dentate and in the 2 subdivisions of the interpositus. Injections into the APA labeled neurons in the dentate and in only the posterior subdivision of the interpositus. In most instances, dentate neurons were more intensely labeled following the cortical injections than interpositus neurons. The transneuronal labeling observed in the dentate nucleus was topographically organized. The dentate region that was labeled following injections into the "arm area" of the APA was caudal and ventral to the dentate region that was labeled following injections into the "arm area" of the primary motor cortex. This observation provides evidence for two "arm areas" in the dentate: one anatomically related to the APA, and the other related to the primary motor cortex. More than one route of transport may be responsible for the labeling of cerebellar neurons. We propose that the labeling observed in the dentate nucleus reflects the pattern of connections in the cerebellothalamocortical pathways that link the dentate with the cerebral cortex. Thus, our observations support the concept proposed by Schell and Strick (J. Neurosci. 4:539-560, '84)--that the cortical targets of the dentate nucleus include both the primary motor cortex and the APA.     

Cruzipain induces both mucosal and systemic protection against Trypanosoma cruzi in mice

Cruzipain, the major cysteinyl proteinase of Trypanosoma cruzi, is expressed by all developmental forms and strains of the parasite and stimulates potent humoral and cellular immune responses during infection in both humans and mice. This information suggested that cruzipain could be used to develop an effective T. cruzi vaccine. To study whether cruzipain-specific T cells could inhibit T. cruzi intracellular replication, we generated cruzipain-reactive CD4(+) Th1 cell lines. These T cells produced large amounts of gamma interferon when cocultured with infected macrophages, resulting in NO production and decreased intracellular parasite replication. To study the protective effects in vivo of cruzipain-specific Th1 responses against systemic T. cruzi challenges, we immunized mice with recombinant cruzipain plus interleukin 12 (IL-12) and a neutralizing anti-IL-4 MAb. These immunized mice developed potent cruzipain-specific memory Th1 cell responses and were significantly protected against normally lethal systemic T. cruzi challenges. Although cruzipain-specific Th1 responses were associated with T. cruzi protective immunity in vitro and in vivo, adoptive transfer of cruzipain-specific Th1 cells alone did not protect BALB/c histocompatible mice, indicating that additional immune mechanisms are important for cruzipain-specific immunity. To study whether cruzipain could induce mucosal immune responses relevant for vaccine development, we prepared recombinant attenuated Salmonella enterica serovar Typhimurium vaccines expressing cruzipain. BALB/c mice immunized with salmonella expressing cruzipain were significantly protected against T. cruzi mucosal infection. Overall, these data indicate that cruzipain is an important T. cruzi vaccine candidate and that protective T. cruzi vaccines will need to induce more than CD4(+) Th1 cells alone.     

Association of defensin beta-1 gene polymorphisms with asthma

BACKGROUND: Defensins are antimicrobial peptides that may take part in airway inflammation and hyperresponsiveness. OBJECTIVE: We characterized the genetic diversity in the defensin beta-1 (DEFB1) locus and tested for an association between common genetic variants and asthma diagnosis. METHODS: To identify single nucleotide polymorphisms (SNPs), we resequenced this gene in 23 self-defined European Americans and 24 African Americans. To test whether DEFB1 genetic variants are associated with asthma, we genotyped 4 haplotype-tag SNPs in 517 asthmatic and 519 control samples from the Nurses' Health Study (NHS) and performed a case-control association analysis. To replicate these findings, we evaluated the DEFB1 polymorphisms in a second cohort from the Childhood Asthma Management Program. RESULTS: Within the NHS, single SNP testing suggested an association between asthma diagnosis and a 5' genomic SNP (g.-1816 T>C; P = .025) and intronic SNP (IVS+692 G>A; P = .054). A significant association between haplotype (Adenine, Cytosine, Thymine, Adenine [ACTA]) and asthma ( P = .024) was also identified. Associations between asthma diagnosis and both DEFB1 polymorphisms were observed in Childhood Asthma Management Program, a second cohort: g.-1816 T>C and IVS+692 G>A demonstrated significant transmission distortion ( P = .05 and .007, respectively). Transmission distortion was not observed in male subjects. The rare alleles (-1816C and +692A) were undertransmitted to offspring with asthma, suggesting a protective effect, contrary to the findings in the NHS cohort. Similar effects were evident at the haplotype level: ACTA was undertransmitted ( P = .04) and was more prominent in female subjects ( P = .007). CONCLUSION: Variation in DEFB1 contributes to asthma diagnosis, with apparent gender-specific effects.     

Epidemiology of tuberculosis in immigrant patients hospitalised in Infectious Diseases Units in Italy: multicentric study

In order to retrospectively evaluate the prevalence of immigrant patients affected by active tuberculosis, we analysed the clinical data of 2255 immigrant patients hospitalised during 2002 in ordinary admission or in Day Hospital in 48 Clinics of Infectious Diseases. In all, 303 patients were affected by active tuberculosis (13.4% of the total immigrant hospitalised patients); 30 patients (9.9%) were also HIV-positive. There was a considerable male gender bias (62.5%); the mean age was 29.7 years; 144 patients were from Africa (47.5%), 72 (23.7%) from Asia, 47 (15.5%) from eastern Europe and 40 (13.2%) from South America. The clinical variants were: pulmonary (57.7%), lymph node (15.8%), meningitis (13.8%), intestinal (4.2%), bone (3.3%), pleurical (2.3%), peritoneal (2.3%) and renal (0.6%). We conclude that tuberculosis is a very frequent disease among immigrants, especially of African origin. The high percentage is due to several factors, such as no vaccine prophylaxis and poor, overcrowded living conditions. It is fundamental to focus on the need to provide better health support for all subjects by setting up screening plans to estimate the real incidence of this pathology and ensure medical treatment to prevent the spread of this infection among immigrants and the local host population.     

Genetics, epigenetics, and the environment: switching, buffering, releasing

Increasing evidence suggests that the interactions between genes and environment might play a critical role in the pathogenesis of complex diseases, such as asthma, that exhibit a heritable component but do not follow Mendel's laws. Gene-environment interactions are extremely complex and not linear, such that the same genetic variants might be associated with opposite phenotypes in different environments. This is particularly evident for innate immunity genes, which operate at the interface between the immune system and the pathogen world. This article examines gene-environment interactions by using CD14 as a model and argues that the conflicting results of epidemiologic studies on CD14*C-159T result from differences in environmental conditions essential to modulate CD14 gene expression. Furthermore, on the basis of how rapidly environmental changes have affected the incidence of immune diseases, I argue that a full understanding of gene-environment interactions requires that epigenetic as well as classical genetic mechanisms be taken into account. Recent data about the effect of diet on gene methylation and the release of hidden genetic variation by impairment of heat shock protein 90-mediated buffering systems offer eloquent examples of how epigenetic mechanisms might affect gene-environment interactions.